It seems as though any one of the mods by themselves would be pretty much useless. And it also seems like in this case it would just be a better idea to go with a whole new intake setup like asr or hsr etc. I have been going through this debate for a little while now, and it seems like buying new runners would be pointless without a new base and plenum, etc. Any advice would be great. THanks.

 

This is something that you are better off using the search function. SLP, AS&M and others make make replacement runners.

That HSR will give you all kinds of power. Unfortunately, if you have to pass smog, you won't. If you need smog legal, you are limited to a Super Ram.

Okay, that's a short summary. Good luck.

 

If you haven't already the better bang for you buck is an upgraded exhaust system. After that you will see more of an increase with intake upgrades.

 

Oh dont worry about that. Basically the whole car is built except for the intake. I just bought it actually. It has zz4 block, edelbrock headers, brand new 10 bolt rear with 3.73's, flowmaster exhaust, accel 58x2 billet throttle body (no idea why), new rims and tires etc, and a completely stock intake setup. O yea, and a hypertech chip. There are crummy air filters and no special gutting or cutting or anything to help the airflow. So basically my motor is starving for air and I already got a couple k&n's that I am waiting for in the main, and I am going to cut out the plastic crap from under the filter. So basically, if i just bought one of the things I mentioned above, would it be like useless by itself? Like wouldn't new runners be pointless if the air has to first travel through the stock plenum anyways? Anyhow, I will be starting school again soon, where I can port out my plenum and any of that kind of stuff. So im open to any ideas. THanks a lot.

 

runners by them selves wont help all that much since the stock base is still there. both together are really restrictive. keeping a 350 from breathing above 4500rpms.

same with replacing a base alone with stock runners. runners are still same restriction.

you might pick up a few cfm over all and make maybe 10hp more or so. but for the price that worth it.

might as well save up and do both at the same time. runners and base. that will give you the best gain

a super ram on a stock L98 with AFPR turned up some, with exhaust mods, can do mid 13's.

i'm was at 13.8's with 2.77 gears on a full exhaust but stock cat L98 TPI. superram will open up lots of power.

but then your heads are a restrictor. replace those and the cam is a restrictor. replace that and your looking to tune it cuz it wont run good. but potential is there

 

Well, when the motor was bought it was a complete engine.

Camshaft: High performance hydraulic roller profile with 235 degrees duration (at .050" tappet left) and .480" maximum valve lift.

Cylinder Heads: Lightweight Corvette aluminum heads with 1.94" intake valves, 1.50" exhaust valves, raised D-shaped exhaust ports, 58cc combustion chambers, angled spark plugs, screw-in rocker arm studs, pushrod guideplates, and raised rocker cover rails.

I honestly don't know if this is all that great...but I figured the whole motor altogether was all performance. So are these "restrictors" as you say, and should I start to work on these first? Or should I go ahead with the intake route?

Thanks again for the help.

 

Pointless? Well, that's a little strong but certainly not a good bang for the buck. You're thinking about it right though. Bolting a 58mm TB to a stock plenum is silly. The opening needs to be opened up and the EGR bump ground down to unlock the full potential. Heck you should do that with a stock TB too. Running large tube runners without opening up the plenum exit holes to match along with porting/changing the base to match is also just throwing away potential gains. Portmatching and aligning the TPI base to the heads is just as important but more involved than just an intake swap.

In my case I'm installing the AS&M runners and Accel base at the same time. The Accel base needed some work to match the runners and is matched to a 1204 gasket on the outlet side. The exit holes in the plenum have already been opened up for the AS&M runners. The Accel base is mismatched with the intake ports of the stock heads but the plan is upgraded heads in the future so I'll just live with that for now.

 

That's the specs for the ZZ through ZZ2 camshaft. Not a good cam for TPI. Your sig says you've got a ZZ4. The ZZ3 and ZZ4 series came with a good cam for TPI.

265/274 deg duration at .006"
208/221 degs duration at .050"
.474"/.510" valve lift with 1.5 rockers
112 deg LSA

The Corvette AL 113 heads are better than the cast iron heads on Fbody L98s but not as good as Vortecs or aftermarket. They respond well to porting.

The intake is your big bottleneck now. You're really at a crossroads. If you like the 3.73 gears and want improved top end then look at the Holley Stealth Ram, TPI Miniram, or converted LT1 intake. If you want to stay TPI due to personal preference or emissions regs than look at the Super Ram, AS&M siamesed runners, or completely ported SLP runners. Run an Accel, TPIS, or Edelbrock base. You'll go as fast or faster with 3.23 or 3.42 gears if you keep the TPI and get a nice mileage boost too.

Spend some times reading through previous posts on this board. Lots of good info related to intakes and overall engine combos that work.